1. Field of the Invention
This invention relates to a package for containing and dispensing compositions that are made with two or more initially separate components. This invention also relates to an assembly that includes a package for a multiple-component composition along with a dispensing actuator for facilitating the mixing of the components.
2. Description of the Related Art
A number of liquid and semi-liquid compositions are made from two or more components that are typically not mixed together until immediately prior to use. For example, certain adhesives such as epoxies are sold in packages that initially keep components of the adhesive separated from each other. Whenever such adhesives are needed for use, the components are mixed together and a chemical reaction between the two components begins. After the components are mixed, the composition is applied to the work site before the composition unduly hardens.
A number of packages have been proposed over the years for separately containing and storing components of multiple-component compositions. An example of one type of commonly-used package for multiple-component compositions is a dual-chamber cartridge that is adapted to fit within a dispensing applicator. The cartridge includes a piston in each chamber, and the applicator typically includes a pair of side-by-side plungers that are adapted to simultaneously apply pressure to both pistons in order to direct components from both chambers at the same time.
Examples of dual-chamber dispensing syringes are described in U.S. Pat. Nos. 5,722,829, 5,624,260, and 4,538,920. In many instances, a static mixer is connected to the outlets of the cartridge for facilitating mixing of the components as the components are directed from the chambers. Often, the plungers of the applicator are connected to a lever so that a mechanical advantage is provided and relatively viscous components can be directed from the chambers and through the static mixer without undue effort.
Unfortunately, dual-chamber cartridges, static mixer and applicator assemblies are not entirely satisfactory for dispensing multiple-component compositions in some instances, particularly in instances where only a relatively small amount of composition is needed. In those instances, large portions of the components may remain in the cartridge after a sufficient amount has been taken for the work at hand. It may be possible to replace the static mixer with a new static mixer and use the remaining portions of the components at a later date, but the components may degrade in the interim.
Moreover, when dual-chamber cartridges are used in health care fields such as dentistry, the user must take care to avoid cross-contamination between patients in offices where the composition from a single cartridge is used in multiple procedures among different patients. The issue of cross-contamination can be addressed by proper handling of the dispensing assembly to ensure that disinfection of the cartridge, applicator and static mixer assembly is accomplished as needed. However, inadequate attention to proper disinfection and handling techniques of the assembly may increase the risk of transferring an infectious disease from one patient to another.
Multiple-component compositions have also been sold in the past in separate bulk containers such as jars or vials. When a quantity of those compositions is needed, the user withdraws a portion of the components from each container using, for example, an applicator brush, swab, spatula or other hand instrument, or by pouring the components from the containers directly onto a mixing pad or mixing well. In this procedure, it is common practice to mix the components together using the hand applicator before applying the mixed composition to the intended location.
However, the use of bulk containers is also not entirely satisfactory. For one thing, it is sometimes difficult to withdraw the desired amount of component from each container in correct proportions. For another thing, it is possible that a user may unintentionally dip the applicator in the second container after the applicator has been placed in the first container and as a result contaminate the contents of the second container. Furthermore, the amount of the components supplied in the bulk containers may be far greater than needed for a particular job, and the remainder of the components may be wasted or degrade over a period of time.
As a result of the foregoing, single use packages have been developed for storing and dispensing of multiple component compositions. Such packages may be formed, for example, by sheets of flexible material having initially separate chambers that receive the components. When the composition is needed, the flexible sheets are squeezed together to decrease the volume in the chambers and direct the components along a path for mixing and dispensing.
Examples of packages that may be used to store and dispense relatively small amounts of multiple component compositions are described in U.S. Pat. Nos. 4,331,264 and 4,952,068. Both of these references describe packages where the components are mixed together in an area downstream of the storage chambers. Canadian patent application no. 2,244,628 also describes a package for dispensing compositions, and includes a pocket for receiving a brush that may be used to apply the mixed composition to an application site.
However, there is a continuing need in the art to improve upon existing packages for multiple-component compositions. For example, there is a demand for an improved package that assures that essentially all of the components are mixed together, so that the correct proportion of the components is present in the resulting mixture. Moreover, there is a need for a package that is relatively easy to manufacture and yet reliably functions to mix and dispense the composition when needed.
The present invention is directed in one aspect to a package for a multiple-component composition that comprises a first sheet and a second sheet connected to the first sheet. At least one of the sheets is made of a flexible material. The package also includes a first chamber, a second chamber and a mixing chamber. Each of the chambers is located between the first sheet and the second sheet. The package also includes an outlet passageway connected to the mixing chamber. The package further includes a first passageway extending from the first chamber to the mixing chamber, and a second passageway extending from the second chamber to the mixing chamber. The mixing chamber is located along a reference axis that extends between the first passageway and the second passageway.
The present invention is also directed in another aspect to a package for a multiple-component composition. In this aspect, the package includes a first sheet and a second sheet connected to the first sheet. At least one of the sheets is made of a flexible material. The package also includes a first chamber, a second chamber and a mixing chamber. Each of the chambers is located between the first sheet and the second sheet. The package includes an outlet passageway connected to the mixing chamber. The package also includes a first passageway extending from the first chamber to the mixing chamber and a second passageway extending from the second chamber to the mixing chamber. The first passageway and the second passageway are spaced apart from each other.
Another aspect of the present invention is also directed toward a package for a multiple-component composition. The package in this aspect includes a first sheet and a second sheet connected to the first sheet in overlying relation. At least one of the sheets is made of a flexible material. The package also includes a first chamber, a second chamber and a mixing chamber. Each of the chambers is located between the first sheet and the second sheet. The package also includes a first passageway connecting the first chamber to the mixing chamber, and a second passageway connecting the second chamber to the mixing chamber. An outlet passageway extends from the mixing chamber and a vent passageway extends from the outlet passageway to the atmosphere. At least one of the first sheet and the second sheet includes a line of weakness that extends along a path between the vent passageway and the outlet passageway. The vent passageway has a cross-sectional area that is less than the cross-sectional area of the outlet passageway.
An additional aspect of the present invention is also directed to a package for a multiple-component composition. In this aspect, the package includes a first sheet and a second sheet connected to the first sheet in overlying relation. At least one of the sheets is made of a flexible material. The package includes a first chamber, a second chamber and a mixing chamber, and each of the chambers is located between the first sheet and the second sheet. The package also includes a first passageway connecting the first chamber to the mixing chamber, and a second passageway connecting the second chamber to the mixing chamber. A first component is received in the first chamber, and a second component is received in the second chamber. At least one of the first sheet and the second sheet is stretched past its yield point in areas next to the mixing chamber and is also initially collapsed in at least some of the same areas when the first component and the second component are received in the first chamber and the second chamber respectively, in order to facilitate passage of the first component and the second component along the first passageway and the second passageway respectively and into the chamber.
The present invention is also directed to a dispensing assembly. The assembly includes a package for a multiple-component composition that includes a first sheet and a second sheet connected to the first sheet in overlying relation. At least one of the sheets is made of a flexible material. The package also includes a first chamber, a first component received in the first chamber, a second chamber, a second component received in the second chamber and a mixing chamber. Each of the chambers is located between the first sheet and the second sheet. The package also includes a first passageway connecting the first chamber to the mixing chamber, a second passageway connecting the second chamber to the mixing chamber and an outlet passageway connected to the mixing chamber. The assembly also includes an actuator that comprises a body with a channel for receiving the package. The body includes wall sections for compressing the first chamber and the second chamber as the package is received in the channel in order to direct the first component and the second component into the mixing chamber.
The present invention is also directed to a method of making a composition from two or more components. The method includes providing a package having at least two chambers and at least two components received in respective chambers, and placing the package in a channel of an actuator. The method also includes moving the package along the channel in order to compress at least one chamber and to direct the respective component along a path for contact with the other component.
The package, dispensing assembly and method of the invention are particularly useful for facilitating dispensing of substantially all of the components in the chambers when needed. As a consequence, the proportion of the components in the resulting composition is essentially the same proportion as intended by the manufacturer, such that the characteristics of the resulting composition can be predicted with relative certainty. The package and assembly of the invention are relatively easy to manufacture and use, and are particularly suitable for use in the field of dentistry to dispense a single dose of dental composition for a single patient. However, the invention is also useful for compositions adapted for household, industrial, commercial, construction and marine applications as well.